Graphene, a strong, lightweight carbon honeycombed structure that's only one atom thick, holds great promise for energy research and development. Recently scientists with the Fluid Interface Reactions, Structures, and Transport (FIRST) Energy Frontier Research Center (EFRC), led by the US Department of Energy's Oak Ridge National Laboratory, revealed graphene can serve as a proton-selective permeable membrane, providing a new basis for streamlined and more efficient energy technologies such as improved fuel cells. The work, published in the March 17 issue of Nature Communications, pinpoints unprecedented proton movement through inherent atomic-scale defects, or gaps, in graphene.

"Now you're able to take a barrier that you can make very thin, like graphene, and change it so you build gates on a molecular scale," says principal investigator Franz Geiger of Northwestern University, the senior author and a FIRST researcher.

The foundation for the study was laid six years ago at ORNL as part of DOE's EFRC initiative to accelerate the scientific breakthroughs needed to build a new 21st century energy economy. The goal of FIRST is to use interdisciplinary research to develop both a fundamental understanding and validated, predictive models of the unique nanoscale environment at fluid-solid interfaces, which will enable transformative advances in electrical energy storage and catalysis, according to FIRST Director David Wesolowski.

Of the paper's 15 authors, all are FIRST researchers with diverse science backgrounds ranging from chemistry to computer modeling. Pooling their expertise, the scientists investigated the mechanisms and structure of graphene using a multifaceted theoretical, experimental, materials synthesis, and computational approach.

Science from the ground up With a tight lattice of carbon reminiscent of chicken wire, pristine graphene was believed to be impenetrable. Current studies, however, have shown that in aqueous solutions, graphene allows surprising numbers of protons to pass through its atomic structure.